The operating efficiency of any conventional commercial laundry dryer is substantially increased, with a proportionate decrease in fuel cost by preheating the air entering the heating unit of the dryer. If gas fired, heated air and the products of combustion are directed downwardly through the housing in which a perforated article-receptive drum is rotatably mounted for tumbling the contents of the drum as said contents are being subjected to the drying effect of the heated air and products of combustion, which, having passed downwardly through the housing, are exhausted from the lower end thereof to be discharged into the atmosphere via a suitable flue.
Considerable fuel savings may be effected in those instances in which the lint and moisture laden, hot exhaust gaseous media are utilized for preheating ambient air which is then introduced into the combustion chamber.